Please backport OCaml fixes to 5.0 branch

[llvmbot]

Bugzilla Link	33987
Resolution	FIXED
Resolved on	Jul 31, 2017 10:40
Version	unspecified
OS	Linux
Blocks	#33196
Reporter	LLVM Bugzilla Contributor
CC	@zmodem

Extended Description

Please backport the following commits to the release_50 branch for OCaml:

r309321: [OCaml] Fix undefined reference to LLVMDumpType() with NDEBUG
r309483: [OCaml] Pass -D/-UNDEBUG through to ocamlc
r309481: [OCaml] Install dynamic libraries in 'stubdirs' directory

The first two combined fix a regression from 4.0 regarding how LLVM exposes dump functions. The third fixes a long-standing bug resulting in compiled OCaml executables being unable to find dynamic OCaml modules.

[zmodem]

Merged in r309590, r309591 and r309592, respectively.